Conventionally, in a lithography process of manufacturing a semiconductor device, a liquid crystal display device, and the like, an exposure apparatus is used for transferring a pattern formed on a mask or reticle (to be generally called a “master” hereinafter) serving as a master, via a projection optical system, onto a wafer or glass plate (to be generally called a “substrate” hereinafter) serving as a substrate to which a resist, or the like, is applied.
In a stage device on the nanometer order used in the exposure apparatus, a high-precision processing machine, and the like, a high-output linear motor is required along with an improvement in performance of the stage device. However, when increasing a current amount flowing to the coil of the linear motor, a heat amount is also greatly increased. Hence, a cooling capacity must be further increased. Also, it is important to increase the cooling capacity of the coil in order to prevent the increase in coil resistance, and damage to the coil wire caused by the increase in temperature of the coil.
An example of the conventional coil support unit in the linear motor is described in Japanese Patent Laid-Open No. 10-309071 (see FIG. 12). In FIG. 12, coils 1a, 1b, and 1c are partially and directly adhered and fixed to jackets 14 and 14′ by epoxy resin or an adhesive, and then, a coolant flows between the jackets. Thus, the coil is directly cooled to collect the generated heat, and the rate of increase in temperature of the coil decreases.
Recently, a higher-speed, higher-precision, and longer-life stage device is required. Hence, the stage device has been developed, which aligns the substrate by two-dimensionally driving, in a noncontact manner, the stage on which the substrate is mounted. As a driving source of the stage device, which drives the stage in a noncontact manner, a plane motor has been known.
The plane motor has a stage, including a magnet portion serving as a movable portion which moves along X and Y directions, and a base serving as a fixed portion. The fixed portion of the plane motor has a plurality of coils stacked in, e.g., a Z direction. A current selectively flows to the coils of each layer to generate a force acting on the stage in a predetermined direction.
In the coil support unit which supports the coil by adhesion, when a thermal expansion force is larger than an adhesion force, the coil may be separated by the thermal expansion force, and the positional accuracy of the coil may be deteriorated. Also, a coil coating may be peeled off, thereby causing a short circuit. A design limitation is imposed on an increase in the adhesion area for increasing the adhesion force. For example, when a coolant directly cools the coil, the adhesion area of the coil must be minimal. Also, when a fixing means fixes the coil in all directions, the coil may locally deform by the thermal expansion force.
Furthermore, in the plane motor where the stacked coils are juxtaposed in the Z direction, when the distance between the movable portion (magnet portion) and the coil becomes longer as the number of layers increases, the heat increases to obtain the same thrust. When forming a coolant channel around the coil in order to decrease the heat, the distance between the movable portion and the coil becomes longer by the channel space, and the heat further increases. Thus, an assembly operation is also difficult to support the coil layer at high precision while ensuring the space for the coolant channel.